https://youtube.com/watch?v=mn34GKTVqMM
windows
zip: https://github.com/hydrusnetwork/hydrus/releases/download/v464/Hydrus.Network.464.-.Windows.-.Extract.only.zip
exe: https://github.com/hydrusnetwork/hydrus/releases/download/v464/Hydrus.Network.464.-.Windows.-.Installer.exe
macOS
app: https://github.com/hydrusnetwork/hydrus/releases/download/v464/Hydrus.Network.464.-.macOS.-.App.dmg
linux
tar.gz: https://github.com/hydrusnetwork/hydrus/releases/download/v464/Hydrus.Network.464.-.Linux.-.Executable.tar.gz
I had a good week. Some images get better colour, and the software now deletes files more neatly.
ICC profiles
tl;dr: Some image colours are better now.
Some images come with an 'ICC profile'. A scan of one ICC-heavy client showed that 10% of all images had them. ICCs are basically colour correction data like 'actually, the blue should be this much more intensely blue than is stored' in a variety of sometimes complicated ways. Some nice cameras attach a fast ICC based on lighting conditions or known defects in the camera, and some image editing software does similar. ICCs are also used for broader and more complicated colour conversion tasks like in the migration from sRGB to HDR formats if you have a new tv/monitor.
Hydrus now has basic ICC tech. It recognises when an image has an ICC and will apply it, converting the rendered colour to 'normal'. This happens right on image load, so it should apply in every media viewer and all new thumbnails. Should work for the server, too. With luck, this will be one of those things where you don't really notice any difference, but you should just have some nicer pictures, mostly photos, in your client. Let me know if you have any files that you know are still not rendering right!
This work took a long time to get done, but a user helped me out with some great examples and more background info on how to handle it all properly. The next step will be to add more indication of when an image has an ICC and add the ability to flip it on and off. Another topic is 'display ICCs', where some artists and other enthusiasts will have an ICC calibrated for their particular monitor or for different display conditions (e.g. 'how would this look like under this lighting?' or '...from this printer?'). Since we have the tech now, I think I should be able to support this sort of ICC conversion too.